US5427751A - Method for using high capacity unsupported regenerable CO2 sorbent - Google Patents
Method for using high capacity unsupported regenerable CO2 sorbent Download PDFInfo
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- US5427751A US5427751A US08/083,392 US8339293A US5427751A US 5427751 A US5427751 A US 5427751A US 8339293 A US8339293 A US 8339293A US 5427751 A US5427751 A US 5427751A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/46—Removing components of defined structure
- B01D53/62—Carbon oxides
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- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
- B01J20/0203—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising compounds of metals not provided for in B01J20/04
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- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
- B01J20/0203—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising compounds of metals not provided for in B01J20/04
- B01J20/0274—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising compounds of metals not provided for in B01J20/04 characterised by the type of anion
- B01J20/0277—Carbonates of compounds other than those provided for in B01J20/043
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- B01J20/04—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising compounds of alkali metals, alkaline earth metals or magnesium
- B01J20/043—Carbonates or bicarbonates, e.g. limestone, dolomite, aragonite
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- B01J20/04—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising compounds of alkali metals, alkaline earth metals or magnesium
- B01J20/046—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising compounds of alkali metals, alkaline earth metals or magnesium containing halogens, e.g. halides
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- B01J20/10—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising silica or silicate
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- B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
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- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
- B01J20/28014—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties characterised by their form
- B01J20/2803—Sorbents comprising a binder, e.g. for forming aggregated, agglomerated or granulated products
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- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/30—Processes for preparing, regenerating, or reactivating
- B01J20/3007—Moulding, shaping or extruding
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- B—PERFORMING OPERATIONS; TRANSPORTING
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- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/30—Processes for preparing, regenerating, or reactivating
- B01J20/32—Impregnating or coating ; Solid sorbent compositions obtained from processes involving impregnating or coating
- B01J20/3202—Impregnating or coating ; Solid sorbent compositions obtained from processes involving impregnating or coating characterised by the carrier, support or substrate used for impregnation or coating
- B01J20/3204—Inorganic carriers, supports or substrates
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- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/30—Processes for preparing, regenerating, or reactivating
- B01J20/32—Impregnating or coating ; Solid sorbent compositions obtained from processes involving impregnating or coating
- B01J20/3231—Impregnating or coating ; Solid sorbent compositions obtained from processes involving impregnating or coating characterised by the coating or impregnating layer
- B01J20/3234—Inorganic material layers
- B01J20/3236—Inorganic material layers containing metal, other than zeolites, e.g. oxides, hydroxides, sulphides or salts
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- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/30—Processes for preparing, regenerating, or reactivating
- B01J20/32—Impregnating or coating ; Solid sorbent compositions obtained from processes involving impregnating or coating
- B01J20/3231—Impregnating or coating ; Solid sorbent compositions obtained from processes involving impregnating or coating characterised by the coating or impregnating layer
- B01J20/3289—Coatings involving more than one layer of same or different nature
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/30—Processes for preparing, regenerating, or reactivating
- B01J20/34—Regenerating or reactivating
- B01J20/3433—Regenerating or reactivating of sorbents or filter aids other than those covered by B01J20/3408 - B01J20/3425
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/30—Processes for preparing, regenerating, or reactivating
- B01J20/34—Regenerating or reactivating
- B01J20/3483—Regenerating or reactivating by thermal treatment not covered by groups B01J20/3441 - B01J20/3475, e.g. by heating or cooling
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- B01J2220/00—Aspects relating to sorbent materials
- B01J2220/40—Aspects relating to the composition of sorbent or filter aid materials
- B01J2220/42—Materials comprising a mixture of inorganic materials
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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- B01J2220/00—Aspects relating to sorbent materials
- B01J2220/50—Aspects relating to the use of sorbent or filter aid materials
- B01J2220/56—Use in the form of a bed
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
- Y02C20/00—Capture or disposal of greenhouse gases
- Y02C20/40—Capture or disposal of greenhouse gases of CO2
Definitions
- This invention relates to the preparation of a sorbent, and especially to the preparation of an unsupported, high capacity, regenerable carbon dioxide sorbent.
- Regenerable solid metal oxide carbon dioxide (CO 2 ) sorbents can be produced via paste extrusions and pelletization methods. However, the cyclical life of these regenerable CO 2 sorbents is limited. Cyclical absorption and desorption operations of solid metal oxide regenerable CO 2 sorbents cause volume changes which result in particle deterioration and breakage; "dusting". This eventually leads to increased sorbent bed pressure drop; resulting in higher power requirements. It is common knowledge in the art that the cyclical life of many regenerable metal oxide sorbents can be increased by the addition of binders or by depositing the active ingredients of the sorbents on inactive supports, such as porous ceramics or carbons, to impart strength and provide high gas/solid contact areas. However, the use of supports and high binder concentrations is undesirable in applications where high CO 2 loading densities, in addition to weight and power considerations, are crucial factors.
- regenerable CO 2 sorbent which provides high loading densities, structural integrity, and high rates of CO 2 sorption.
- This invention discloses a regenerable carbon dioxide (CO 2 ) sorbent, a process for producing said regenerable CO 2 sorbent.
- the sorbent consists of pellets comprised of silver carbonate, binders, and a CO 2 sorption promoter, and is prepared by mixing silver carbonate pellets with a alkali metal silicate and alkaline earth metal salt binders, and an alkali metal carbonate CO 2 sorption promoter.
- the preparation of the sorbent in the present invention consists of forming silver carbonate into pellets of varying shapes, which are held together by electrostatic forces, and contacting these pellets with an aqueous solution containing alkali metal silicate and alkali metal carbonate.
- the pellets are dried to remove excess solvent, and are contacted with a soluble alkaline earth metal salt which forms an additional external coating; further enhancing pellet strength. Note, heat and vacuum can be applied to accelerate drying.
- An aqueous solution is prepared for contact with silver carbonate by dissolving alkali metal silicate and alkali metal carbonate in a solvent.
- the solution is intimately contacted with the silver carbonate, causing the alkali metal carbonate to impregnate the pellet, and the alkali metal silicate and silver carbonate to react forming a silicate coating.
- the intimate contact can be accomplished by any method which provides gentle tumbling of the pellets, such as a rotary tumbler, or other suitable mixing device known in the art.
- the pellets are then dried; any method which will insure uniform deposition of the alkali metal silicate and alkali metal carbonate can be utilized, such as a rotary evaporator.
- a solution of alkaline earth metal salt is prepared and intimately contacted with the dried pellets, as described above.
- the pellets are again dried, and sieved to remove dust and fines. Once this is complete, the pellets are heated to a temperature sufficient to convert the silver carbonate to silver oxide; liberating CO 2 .
- the preferred solvent is water, although it is possible to utilize any solvent which is inert with relation to the components of the sorbent.
- the silver carbonate pellets can either be purchased or fabricated from powder via techniques conventionally known in the art, such as utilizing pelletizers or tablet presses.
- the pellet size limited by system pressure drop considerations, typically ranges from about 0.30 mm to about 3.00 mm, with a pellet, size between about 0.60 mm to about 1.50 mm preferred for closed system applications.
- the preferred alkaline metal silicates include sodium and potassium silicate, and mixtures thereof, although it is feasible to utilize other alkali metal silicates, which are soluble in the selected solvent.
- the silicate forms a thin exterior coating which imparts strength to the pellet structure.
- the desirable amount of silicate is determined via a balance between the optimum structural integrity and maximum reaction rates. Large amounts of silicate impart strength, but also clog the pores reducing sorption rates. Approximately 3.0 wt % to about 8.0 wt % silicate is preferred, with about 5.0 wt % especially preferred.
- Alkali metal carbonates such as carbonated of cesium, potassium, and sodium, and mixtures thereof, distribute throughout the pellet's interior structure and serve as a CO 2 sorption promoters.
- the high pH associated with alkali metal carbonates enhances the CO 2 sorption rate.
- silver oxide has only a moderately alkaline pH, approximately 10.2, the addition of the alkali metal carbonate significantly increases the pellet's alkalinity; enhancing the rate of CO 2 sorption.
- An alkali metal carbonate wt % of between about 8.0 wt % and about 20.0 wt % is preferred, with about 10.0 wt % especially preferred.
- the alkaline earth metal salt binder concentration is preferably between about 2.0 wt % to about 5.0 wt %, with about 3.0 wt % especially preferred.
- factors such as structural integrity and sorption rates must be taken into consideration when determining the amount of alkaline earth metal salt binder to be utilized.
- Various alkaline earth metal salt binders can be utilized, with nitrates and chlorides of calcium, magnesium, and barium, and mixtures thereof preferred; such as calcium chloride, magnesium chloride, barium nitrate, calcium nitrate, among others.
- the wt % of silver carbonate, alkali metal silicate, alkali metal carbonate, and alkaline earth metal salt to utilized are determined by the desired wt % of each in the final product. Any solvent used in the production process is evaporated.
- the prepared sorbent once having been screened to remove any dust and fines, can be loaded into a reactor for the removal of CO 2 from a gaseous stream, typically air.
- the sorbent is then activated for CO 2 sorption by heating it to temperatures sufficient of convert the silver carbonate to silver oxide. Typically these temperatures will be about 160° C. to about 220° C. Note, temperatures above about 250° C. can irreversibly damage the silver oxide sorption abilities.
- the sorbent is capable of removing CO 2 .
- air in a closed environment is passed through the reactor where the alkali metal carbonate reacts with the CO 2 and water in the air to form the bicarbonate ion.
- the silver oxide then reacts with the bicarbonate ion to form silver carbonate, alkali metal carbonate, and water; leaving the alkali metal carbonate uninhibited from continuing to remove carbon dioxide from the air stream.
- the reactor bed loses its CO 2 sorption capabilities and is ready for regeneration.
- Regeneration consists of heating the sorbent bed to a temperature sufficient to cause CO 2 liberation; converting the silver carbonate to silver oxide. Typically temperatures between about 160° C. to about 0° C. are sufficient for CO 2 liberation.
- the sorbent Since the sorbent is unsupported, no inert support is utilized, it contains a higher silver oxide density than the prior art. Also, due to the binder coating, the sorbent resists dusting and degradation for at least 50 absorption/desorption cycles; while other regenerable metal oxide sorbents, known in the art, begin dusting in the very early cycles, if not immediately.
- the following is a generic method which can be utilized to produce a carbon dioxide sorbent comprised of: 2.0 wt % to 5.0 wt % calcium nitrate, 3.0 wt % to 5.0 wt % sodium silicate, 10.0 wt % to 20.0 wt % potassium carbonate, and 70.0 wt % to 85.0 wt % silver carbonate.
- a sodium silicate/potassium carbonate solution is mixed with the pellets. To insure uniform coating, a rotating flask is utilized. The aqueous solution is added at a level that provides 3.0 to 5.0 wt % sodium silicate and 10.0 to 20.0 wt % of the potassium carbonate to the pellet.
- the silicate uniformly concentrates on the exterior surface of the gently tumbling pellets and serves to enhance the structural integrity of the pellet.
- the potassium carbonate is uniformly distributed within the pellet and serves to enhance the rate of CO 2 sorption.
- the excess aqueous solvent is evaporated from the solution/pellet mixture by using a rotating vacuum flash evaporator and applying heat to the mixture to a temperature level ranging from 50° C. to 90° C.
- Use of the rotating flash evaporator insures that the sodium silicate and potassium carbonate are uniformly deposited.
- the coated/impregnated pellets are sieved prior to use to remove fines and dust.
- the pellets are packed within a reactor.
- the reactor is heated to a temperature level between 160° C. to 220° C. to convert the silver carbonate to silver oxide.
- An air purge flow through the bed assists in the removal of the CO 2 and water released from the pellets.
- the sorbent is ready to remove CO 2 . This procedure is repeated when it is required to regenerate the CO 2 sorption capabilities of the sorbent.
- Pellets prepared by this example have been shown to have CO 2 loading densities ranging from about 12.0 to 15.0 lbs/ft 3 ; between about 0.274 to about 0.340 moles/ft 3 .
- This invention relates to the production of a regenerable CO 2 sorbent capable of high CO 2 loading densities, and relatively devoid of the low CO 2 sorption rates and dusting problems which plague the art of regenerable metal oxide CO 2 sorbents. Since this sorbent doesn't require a support, contains a relatively low binder content, and has a high metal oxide density, it consumes minimum volume; making it ideal for closed environmental applications.
Abstract
A technique for preparing an unsupported, high capacity CO2 sorbent. The sorbent is comprised of silver carbonate, alkali metal silicate and alkaline earth metal salt binders for structural integrity, and alkali metal carbonate for CO2 sorption promotion. The sorbent disclosed in this invention has a high silver oxide density, consumes minimum volume, exhibits high CO2 absorption rates, and resists dusting and degradation for at least 50 absorption/desorption cycles.
Description
This is a continuation of application Ser. No. 07/763,858 filed on Sep. 23, 1991, now abandoned, which was a divisional of application Ser. No. 07/490,016 filed Mar. 7, 1990 now U.S. Pat. No. 5,079,209.
This invention relates to the preparation of a sorbent, and especially to the preparation of an unsupported, high capacity, regenerable carbon dioxide sorbent.
Regenerable solid metal oxide carbon dioxide (CO2) sorbents can be produced via paste extrusions and pelletization methods. However, the cyclical life of these regenerable CO2 sorbents is limited. Cyclical absorption and desorption operations of solid metal oxide regenerable CO2 sorbents cause volume changes which result in particle deterioration and breakage; "dusting". This eventually leads to increased sorbent bed pressure drop; resulting in higher power requirements. It is common knowledge in the art that the cyclical life of many regenerable metal oxide sorbents can be increased by the addition of binders or by depositing the active ingredients of the sorbents on inactive supports, such as porous ceramics or carbons, to impart strength and provide high gas/solid contact areas. However, the use of supports and high binder concentrations is undesirable in applications where high CO2 loading densities, in addition to weight and power considerations, are crucial factors.
What is needed in the art is a regenerable CO2 sorbent which provides high loading densities, structural integrity, and high rates of CO2 sorption.
This invention discloses a regenerable carbon dioxide (CO2) sorbent, a process for producing said regenerable CO2 sorbent. The sorbent consists of pellets comprised of silver carbonate, binders, and a CO2 sorption promoter, and is prepared by mixing silver carbonate pellets with a alkali metal silicate and alkaline earth metal salt binders, and an alkali metal carbonate CO2 sorption promoter.
The foregoing and other features and advantages of the present invention will become more apparent from the following description and accompanying drawings.
The preparation of the sorbent in the present invention consists of forming silver carbonate into pellets of varying shapes, which are held together by electrostatic forces, and contacting these pellets with an aqueous solution containing alkali metal silicate and alkali metal carbonate. The pellets are dried to remove excess solvent, and are contacted with a soluble alkaline earth metal salt which forms an additional external coating; further enhancing pellet strength. Note, heat and vacuum can be applied to accelerate drying.
An aqueous solution is prepared for contact with silver carbonate by dissolving alkali metal silicate and alkali metal carbonate in a solvent. The solution is intimately contacted with the silver carbonate, causing the alkali metal carbonate to impregnate the pellet, and the alkali metal silicate and silver carbonate to react forming a silicate coating. The intimate contact can be accomplished by any method which provides gentle tumbling of the pellets, such as a rotary tumbler, or other suitable mixing device known in the art. The pellets are then dried; any method which will insure uniform deposition of the alkali metal silicate and alkali metal carbonate can be utilized, such as a rotary evaporator. A solution of alkaline earth metal salt is prepared and intimately contacted with the dried pellets, as described above. The pellets are again dried, and sieved to remove dust and fines. Once this is complete, the pellets are heated to a temperature sufficient to convert the silver carbonate to silver oxide; liberating CO2.
The preferred solvent is water, although it is possible to utilize any solvent which is inert with relation to the components of the sorbent.
The silver carbonate pellets can either be purchased or fabricated from powder via techniques conventionally known in the art, such as utilizing pelletizers or tablet presses. The pellet size, limited by system pressure drop considerations, typically ranges from about 0.30 mm to about 3.00 mm, with a pellet, size between about 0.60 mm to about 1.50 mm preferred for closed system applications.
The preferred alkaline metal silicates include sodium and potassium silicate, and mixtures thereof, although it is feasible to utilize other alkali metal silicates, which are soluble in the selected solvent. The silicate forms a thin exterior coating which imparts strength to the pellet structure. The desirable amount of silicate is determined via a balance between the optimum structural integrity and maximum reaction rates. Large amounts of silicate impart strength, but also clog the pores reducing sorption rates. Approximately 3.0 wt % to about 8.0 wt % silicate is preferred, with about 5.0 wt % especially preferred.
Alkali metal carbonates, such as carbonated of cesium, potassium, and sodium, and mixtures thereof, distribute throughout the pellet's interior structure and serve as a CO2 sorption promoters. As is well known in the art, the high pH associated with alkali metal carbonates enhances the CO2 sorption rate. Since silver oxide has only a moderately alkaline pH, approximately 10.2, the addition of the alkali metal carbonate significantly increases the pellet's alkalinity; enhancing the rate of CO2 sorption. An alkali metal carbonate wt % of between about 8.0 wt % and about 20.0 wt % is preferred, with about 10.0 wt % especially preferred.
The alkaline earth metal salt binder concentration is preferably between about 2.0 wt % to about 5.0 wt %, with about 3.0 wt % especially preferred. As with the alkali metal silicate, factors such as structural integrity and sorption rates must be taken into consideration when determining the amount of alkaline earth metal salt binder to be utilized. Various alkaline earth metal salt binders can be utilized, with nitrates and chlorides of calcium, magnesium, and barium, and mixtures thereof preferred; such as calcium chloride, magnesium chloride, barium nitrate, calcium nitrate, among others.
The wt % of silver carbonate, alkali metal silicate, alkali metal carbonate, and alkaline earth metal salt to utilized are determined by the desired wt % of each in the final product. Any solvent used in the production process is evaporated.
The prepared sorbent, once having been screened to remove any dust and fines, can be loaded into a reactor for the removal of CO2 from a gaseous stream, typically air. The sorbent is then activated for CO2 sorption by heating it to temperatures sufficient of convert the silver carbonate to silver oxide. Typically these temperatures will be about 160° C. to about 220° C. Note, temperatures above about 250° C. can irreversibly damage the silver oxide sorption abilities. After cooling to near ambient temperatures, the sorbent is capable of removing CO2. For example, air in a closed environment is passed through the reactor where the alkali metal carbonate reacts with the CO2 and water in the air to form the bicarbonate ion. The silver oxide then reacts with the bicarbonate ion to form silver carbonate, alkali metal carbonate, and water; leaving the alkali metal carbonate uninhibited from continuing to remove carbon dioxide from the air stream.
Once the silver oxide content is converted to the carbonate form, the reactor bed loses its CO2 sorption capabilities and is ready for regeneration. Regeneration consists of heating the sorbent bed to a temperature sufficient to cause CO2 liberation; converting the silver carbonate to silver oxide. Typically temperatures between about 160° C. to about 0° C. are sufficient for CO2 liberation.
Since the sorbent is unsupported, no inert support is utilized, it contains a higher silver oxide density than the prior art. Also, due to the binder coating, the sorbent resists dusting and degradation for at least 50 absorption/desorption cycles; while other regenerable metal oxide sorbents, known in the art, begin dusting in the very early cycles, if not immediately.
The following is a generic method which can be utilized to produce a carbon dioxide sorbent comprised of: 2.0 wt % to 5.0 wt % calcium nitrate, 3.0 wt % to 5.0 wt % sodium silicate, 10.0 wt % to 20.0 wt % potassium carbonate, and 70.0 wt % to 85.0 wt % silver carbonate.
1. The silver carbonate powder pelletized in a rotating disk agglomerator, and sieved to provide between 0.60 mm to 1.40 mm diameter pellets.
2. A sodium silicate/potassium carbonate solution is mixed with the pellets. To insure uniform coating, a rotating flask is utilized. The aqueous solution is added at a level that provides 3.0 to 5.0 wt % sodium silicate and 10.0 to 20.0 wt % of the potassium carbonate to the pellet. The silicate uniformly concentrates on the exterior surface of the gently tumbling pellets and serves to enhance the structural integrity of the pellet. The potassium carbonate is uniformly distributed within the pellet and serves to enhance the rate of CO2 sorption.
3. The excess aqueous solvent is evaporated from the solution/pellet mixture by using a rotating vacuum flash evaporator and applying heat to the mixture to a temperature level ranging from 50° C. to 90° C. Use of the rotating flash evaporator insures that the sodium silicate and potassium carbonate are uniformly deposited.
4. Calcium nitrate, to provide 2.0 wt % to 5.0 wt %, is then added as in step 2 to further enhance the structural integrity of the pellet. The wetted pellets are dried as in step 3.
5. The coated/impregnated pellets are sieved prior to use to remove fines and dust.
6. The pellets are packed within a reactor. The reactor is heated to a temperature level between 160° C. to 220° C. to convert the silver carbonate to silver oxide. An air purge flow through the bed assists in the removal of the CO2 and water released from the pellets. After cooling the beds to near ambient conditions, the sorbent is ready to remove CO2. This procedure is repeated when it is required to regenerate the CO2 sorption capabilities of the sorbent. Pellets prepared by this example have been shown to have CO2 loading densities ranging from about 12.0 to 15.0 lbs/ft3 ; between about 0.274 to about 0.340 moles/ft3.
This invention relates to the production of a regenerable CO2 sorbent capable of high CO2 loading densities, and relatively devoid of the low CO2 sorption rates and dusting problems which plague the art of regenerable metal oxide CO2 sorbents. Since this sorbent doesn't require a support, contains a relatively low binder content, and has a high metal oxide density, it consumes minimum volume; making it ideal for closed environmental applications.
Although this invention has been shown and described with respect to detailed embodiments thereof, it will be understood by those skilled in the art that various changes in form and detail thereof may be made without departing from the spirit and scope of the claimed invention.
Claims (5)
1. A method for utilizing a regenerable metal oxide CO2 sorbent, comprising the steps of:
(a) loading a sorbent in a reactor to form a sorbent bed, wherein the sorbent loaded in the reactor is produced by a process comprising the steps of:
(1) pelletizing silver carbonate, wherein pellets of silver carbonate are formed,
(2) preparing an aqueous solution of alkali metal silicate and alkali metal carbonate,
(3) contacting the silver carbonate pellets with the alkali metal silicate/alkali metal carbonate aqueous solution, thereby forming silicate coated, alkali metal impregnated silver carbonate pellets,
(4) drying the silicate coated, alkali metal carbonate impregnated silver carbonate pellets,
(5) preparing an aqueous solution of alkaline earth metal salt,
(6) contacting the silicate coated, alkali metal carbonate impregnated silver carbonate pellets with the alkaline earth metal salt aqueous solution, thereby forming an alkaline earth metal salt coating on the silicate coated, alkali metal carbonate impregnated silver carbonate pellets,
(7) drying the alkaline earth metal salt/silicate coated, alkali metal carbonate impregnated silver carbonate pellets, and
(8) heating the pellets from step 7 to a temperature sufficient to convert the silver carbonate to silver oxide to form a silver oxide containing sorbent bed;
(b) passing a gaseous stream containing CO2 and water over the silver oxide containing sorbent bed, under conditions sufficient to sorb CO2.
2. The method of claim 1 wherein the sorbent bed is heated to between about 160° C. to about 220° C. in step 8.
3. The method of claim 1 wherein the alkali metal silicate is selected from the group consisting of sodium silicate, potassium silicate, and mixtures thereof.
4. The method of claim 1 wherein the alkali metal carbonate is selected from the group consisting of cesium carbonate, potassium carbonate, sodium carbonate, and mixtures thereof.
5. The method of claim 1 wherein the alkaline earth metal salt is selected from the group consisting of calcium chloride, magnesium chloride, barium chloride, calcium nitrate, magnesium nitrate, barium nitrate and mixtures thereof.
Priority Applications (1)
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US08/083,392 US5427751A (en) | 1990-03-07 | 1993-06-28 | Method for using high capacity unsupported regenerable CO2 sorbent |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
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US07/490,016 US5079209A (en) | 1990-03-07 | 1990-03-07 | Preparation of high capacity unsupported regenerable co2 sorbent |
US76385891A | 1991-09-23 | 1991-09-23 | |
US08/083,392 US5427751A (en) | 1990-03-07 | 1993-06-28 | Method for using high capacity unsupported regenerable CO2 sorbent |
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US76385891A Continuation | 1990-03-07 | 1991-09-23 |
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US5427751A true US5427751A (en) | 1995-06-27 |
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US07/490,016 Expired - Lifetime US5079209A (en) | 1990-03-07 | 1990-03-07 | Preparation of high capacity unsupported regenerable co2 sorbent |
US08/083,392 Expired - Fee Related US5427751A (en) | 1990-03-07 | 1993-06-28 | Method for using high capacity unsupported regenerable CO2 sorbent |
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US07/490,016 Expired - Lifetime US5079209A (en) | 1990-03-07 | 1990-03-07 | Preparation of high capacity unsupported regenerable co2 sorbent |
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US (2) | US5079209A (en) |
EP (1) | EP0445776B1 (en) |
JP (1) | JP3396228B2 (en) |
AT (1) | ATE95077T1 (en) |
DE (1) | DE69100413T2 (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
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US20040065205A1 (en) * | 2002-10-03 | 2004-04-08 | Nalette Timothy A. | Encapsulated CO2 H2O sorbent |
US20040261617A1 (en) * | 2003-06-30 | 2004-12-30 | Stewart Albert E. | Methods and systems for pressure swing regeneration for hydrogen generation |
US20050232858A1 (en) * | 2003-11-26 | 2005-10-20 | Hampden-Smith Mark J | Fuel reformer catalyst and absorbent materials |
US7089933B2 (en) | 2002-10-25 | 2006-08-15 | Hamilton Sundstrand | CO2 sorbent for inhalation drug therapy system |
US7267811B2 (en) | 2003-11-26 | 2007-09-11 | Cabot Corporation | Fuel reformer catalyst and absorbent materials |
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US5079209A (en) * | 1990-03-07 | 1992-01-07 | United Technologies Corporation | Preparation of high capacity unsupported regenerable co2 sorbent |
US5214019A (en) * | 1992-02-24 | 1993-05-25 | United Technologies Corporation | Enhancing carbon dioxide sorption rates using hygroscopic additives |
US6280503B1 (en) * | 1999-08-06 | 2001-08-28 | Air Products And Chemicals, Inc. | Carbon dioxide adsorbents containing magnesium oxide suitable for use at high temperatures |
GB0020656D0 (en) * | 2000-08-23 | 2000-10-11 | Molecular Products Ltd | Improvements in or relating to carbon dioxide absorbent formulations |
CN1795979B (en) * | 2004-12-23 | 2010-11-10 | 韩国电力公社 | High strength drying regeneration CO2 adsorbent |
US7820591B2 (en) * | 2005-01-04 | 2010-10-26 | Korea Electric Power Corporation | Highly attrition resistant and dry regenerable sorbents for carbon dioxide capture |
JP4781208B2 (en) * | 2006-09-13 | 2011-09-28 | 三栄源エフ・エフ・アイ株式会社 | Powder granulation method and easily dispersible and easily soluble granule composition |
BR122018070109B1 (en) * | 2007-11-15 | 2019-06-04 | Rutgers, The State University Of New Jersey | Method for making a pottery by using a greenhouse gas |
CN111974344A (en) * | 2020-08-18 | 2020-11-24 | 上海大学 | Carbon dioxide capture agent and preparation method thereof |
Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1207273A (en) * | 1914-07-17 | 1916-12-05 | John Cadman | Absorbent medium for carbonic-acid gas. |
US3232028A (en) * | 1962-07-02 | 1966-02-01 | Isomet Corp | Composition and method for absorption and regeneration of carbon dioxide |
US3489693A (en) * | 1967-04-03 | 1970-01-13 | Automatic Sprinkler Corp | Carbon dioxide absorbent |
US3557011A (en) * | 1967-07-31 | 1971-01-19 | Mc Donnell Douglas Corp | Co2 sorption material |
US4407723A (en) * | 1981-05-27 | 1983-10-04 | Her Majesty The Queen In Right Of Canada, As Represented By The Minister Of National Defence | Absorption of carbon dioxide |
US5045295A (en) * | 1989-02-10 | 1991-09-03 | Uop | Silicate treatment of molecular sieve agglomerates |
US5079209A (en) * | 1990-03-07 | 1992-01-07 | United Technologies Corporation | Preparation of high capacity unsupported regenerable co2 sorbent |
US5214019A (en) * | 1992-02-24 | 1993-05-25 | United Technologies Corporation | Enhancing carbon dioxide sorption rates using hygroscopic additives |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2395842A (en) * | 1930-07-14 | 1946-03-05 | Borgstrom Parry | Gas absorbent material and process of making the same |
US3579305A (en) * | 1968-07-25 | 1971-05-18 | Beckman Instruments Inc | Scrubber apparatus |
US3847837A (en) * | 1972-04-25 | 1974-11-12 | Foote Mineral Co | Carbon dioxide absorbent granules |
GB1505529A (en) * | 1974-06-14 | 1978-03-30 | Mo Och Domsjoe Ab | Method for the oxygen-gas delignification of lignocellulosic material and apparatus for carrying out the method |
US4284528A (en) * | 1979-03-12 | 1981-08-18 | Conoco Inc. | Synthetic CO2 acceptor |
US4304761A (en) * | 1980-11-28 | 1981-12-08 | Ford Motor Company | Method of treating exhaust gases from a methanol fueled internal combustion engine |
US4552767A (en) * | 1984-09-27 | 1985-11-12 | General Foods Corporation | Method of packaging coffee with carbon dioxide sorbent |
US4582819A (en) * | 1984-12-11 | 1986-04-15 | Union Oil Company Of California | Catalytic absorbent and a method for its preparation |
JPS63281100A (en) * | 1987-05-13 | 1988-11-17 | Hitachi Ltd | Preparation of solidified body for iodine adsorbent |
US4758251A (en) * | 1987-05-26 | 1988-07-19 | Allied-Signal Inc. | Separation of gases through gas enrichment membrane composites |
-
1990
- 1990-03-07 US US07/490,016 patent/US5079209A/en not_active Expired - Lifetime
-
1991
- 1991-03-06 EP EP91103416A patent/EP0445776B1/en not_active Expired - Lifetime
- 1991-03-06 AT AT91103416T patent/ATE95077T1/en not_active IP Right Cessation
- 1991-03-06 DE DE91103416T patent/DE69100413T2/en not_active Expired - Fee Related
- 1991-03-07 JP JP06803891A patent/JP3396228B2/en not_active Expired - Fee Related
-
1993
- 1993-06-28 US US08/083,392 patent/US5427751A/en not_active Expired - Fee Related
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1207273A (en) * | 1914-07-17 | 1916-12-05 | John Cadman | Absorbent medium for carbonic-acid gas. |
US3232028A (en) * | 1962-07-02 | 1966-02-01 | Isomet Corp | Composition and method for absorption and regeneration of carbon dioxide |
US3489693A (en) * | 1967-04-03 | 1970-01-13 | Automatic Sprinkler Corp | Carbon dioxide absorbent |
US3557011A (en) * | 1967-07-31 | 1971-01-19 | Mc Donnell Douglas Corp | Co2 sorption material |
US4407723A (en) * | 1981-05-27 | 1983-10-04 | Her Majesty The Queen In Right Of Canada, As Represented By The Minister Of National Defence | Absorption of carbon dioxide |
US5045295A (en) * | 1989-02-10 | 1991-09-03 | Uop | Silicate treatment of molecular sieve agglomerates |
US5079209A (en) * | 1990-03-07 | 1992-01-07 | United Technologies Corporation | Preparation of high capacity unsupported regenerable co2 sorbent |
US5214019A (en) * | 1992-02-24 | 1993-05-25 | United Technologies Corporation | Enhancing carbon dioxide sorption rates using hygroscopic additives |
Non-Patent Citations (4)
Title |
---|
Colombo, G. V. "Study of CO2 Sorbents for Extravehicular Activity" NASA Paper CR114632, published Jul. 1973. |
Colombo, G. V. Study of CO 2 Sorbents for Extravehicular Activity NASA Paper CR114632, published Jul. 1973. * |
Nacheff, M. S., et al. "Metal Oxide Regenerable Carbon Dioxide Removal System for an Advanced Portable Life Support System", SAE Technical Paper Series Paper #891595, published 1989. |
Nacheff, M. S., et al. Metal Oxide Regenerable Carbon Dioxide Removal System for an Advanced Portable Life Support System , SAE Technical Paper Series Paper 891595, published 1989. * |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20040065205A1 (en) * | 2002-10-03 | 2004-04-08 | Nalette Timothy A. | Encapsulated CO2 H2O sorbent |
US6797043B2 (en) | 2002-10-03 | 2004-09-28 | Hamilton Sundstrand | Encapsulated CO2 H2O sorbent |
US7089933B2 (en) | 2002-10-25 | 2006-08-15 | Hamilton Sundstrand | CO2 sorbent for inhalation drug therapy system |
US20040261617A1 (en) * | 2003-06-30 | 2004-12-30 | Stewart Albert E. | Methods and systems for pressure swing regeneration for hydrogen generation |
US6942719B2 (en) * | 2003-06-30 | 2005-09-13 | The Boeing Company | Methods and systems for pressure swing regeneration for hydrogen generation |
US20050232858A1 (en) * | 2003-11-26 | 2005-10-20 | Hampden-Smith Mark J | Fuel reformer catalyst and absorbent materials |
US7264788B2 (en) | 2003-11-26 | 2007-09-04 | Cabot Corporation | Fuel reformer catalyst and absorbent materials |
US7267811B2 (en) | 2003-11-26 | 2007-09-11 | Cabot Corporation | Fuel reformer catalyst and absorbent materials |
Also Published As
Publication number | Publication date |
---|---|
ATE95077T1 (en) | 1993-10-15 |
EP0445776B1 (en) | 1993-09-29 |
EP0445776A2 (en) | 1991-09-11 |
EP0445776A3 (en) | 1991-11-06 |
DE69100413D1 (en) | 1993-11-04 |
JPH04222629A (en) | 1992-08-12 |
DE69100413T2 (en) | 1994-04-28 |
JP3396228B2 (en) | 2003-04-14 |
US5079209A (en) | 1992-01-07 |
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